The present disclosure is related to extended area light sources suitable for illuminating a display or graphic, commonly referred to as backlights.
Backlights are used to illuminate displays such as LCD computer monitors, cellphone displays, personal digital assistants, and other hand-held devices. In an effort to reduce weight, hollow backlights have been developed. Some hollow backlights have utilized symmetric concentrators or light injectors, including symmetric parabolic concentrators, in combination with a light source to direct light into the hollow light cavity. However, such light injectors increase the total size of the display because of the volume of the symmetric light injector. The increase in the display size is due to an increased bezel width required to accommodate the size of the symmetric light injector.
FIG. 8 illustrates a prior art backlight 800 utilizing a symmetric light injector. The backlight 800 has a front reflector 802, back reflector 804, and side reflector 806 that defines the light cavity 808. Between the light source 810 and the light cavity 808, a compound parabolic concentrator 812 directs light from the light source into the light cavity. The bezel width is identified as “W”.